maybeBroadcastArray
Broadcast an ndarray to a specified shape if and only if the specified shape differs from the provided ndarray's shape.
Usage
var maybeBroadcastArray = require( '@stdlib/ndarray/maybe-broadcast-array' );
maybeBroadcastArray( x, shape )
Broadcasts an ndarray to a specified shape if and only if the specified shape differs from the provided ndarray's shape.
var array = require( '@stdlib/ndarray/array' );
// Create a 2x2 ndarray:
var x = array( [ [ 1, 2 ], [ 3, 4 ] ] );
// returns <ndarray>
// Broadcast to a 2x2x2 ndarray:
var y = maybeBroadcastArray( x, [ 2, 2, 2 ] );
// returns <ndarray>
Notes
- The function throws an error if a provided ndarray is incompatible with a provided shape.
- If a provided ndarray has the same shape as the specified shape, the function returns the provided ndarray.
- If a provided ndarray has a different (broadcast compatible) shape than the specified shape, the function returns a new read-only ndarray view of the provided ndarray's data. The view is typically not contiguous. As more than one element of a returned view may refer to the same memory location, writing to the input ndarray may affect multiple elements. If you need to write to the input ndarray, copy the ndarray before broadcasting.
Examples
var array = require( '@stdlib/ndarray/array' );
var numel = require( '@stdlib/ndarray/base/numel' );
var ind2sub = require( '@stdlib/ndarray/ind2sub' );
var maybeBroadcastArray = require( '@stdlib/ndarray/maybe-broadcast-array' );
// Create a 2x2 array:
var x = array( [ [ 1, 2 ], [ 3, 4 ] ] );
// returns <ndarray>
// Broadcast the array to 3x2x2:
var y = maybeBroadcastArray( x, [ 3, 2, 2 ] );
// returns <ndarray>
// Retrieve the shape:
var sh = y.shape;
// returns [ 3, 2, 2 ]
// Retrieve the number of elements:
var N = numel( sh );
// Loop through the array elements...
var i;
for ( i = 0; i < N; i++ ) {
console.log( 'Y[%s] = %d', ind2sub( sh, i ).join( ', ' ), y.iget( i ) );
}